POS0752 MUSCULOSKELETAL INVOLVEMENT IMPAIRS QUALITY OF LIFE IN JUVENILE PSORIATIC ARTHRITIS
Authors: P. Collado, N. Palmou-Fontana, P. Mesa del Castillo, B. P. Magallares López, I. Calvo, G. Diaz-Cordobes, E. Moreno Ruzafa, M. Steiner, J. C. Lopez Robledillo
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Juvenile psoriatic arthritis (JPsA) is one of the least common subtypes of JIA. Information on JPsA is mainly clinical, but scarce regarding the impact of musculoskeletal involvement on children's quality of life. <h3>Objectives</h3> To describe the clinical and ultrasound (US) characteristics of children with JPsA, and to assess their impact using a composite quality of life index, the PsAID (Psoriasis Arthritis Impact of Disease). <h3>Methods</h3> A multicentre cross-sectional observational study recruited consecutive JPsA patients, from January-2020 to May-2022. Inclusion criteria: 1/ age at onset ≤ 16 years, 2/ diagnosis by the prescribing physician based on one of the 2 JPsA diagnostic classification systems (ILAR or Vancouver). All were assessed clinically and US (independently) and completed two questionnaires: PsAID (1) and Child Health Assessment Questionnaire (CHAQ, to measure physical disability). Statistics included correlation Spearman (rho) and PsAID was identified as the dependent variable. <h3>Results</h3> The 48 children included (mean age at inclusion 11±4 years), 71% girls, 67% had oligoarthritis and 80% psoriasis in a first or second-degree relative. Mostly arthritis started before the psoriasis. The median time lag between the diagnosis and the onset of specific musculoskeletal manifestations was 1 year; interquartile range 0.5-2. ANA and HLAB27 were present in 19 (40%) and 5 (10%) of the children, respectively. A history of axial inflammatory symptoms was present in 3 (5%) patients, and unilateral sacroiliitis was confirmed by MRI in only one patient. Psoriasis and dactylitis were the most frequent manifestations identified (≥50%), while uveitis was less common (12%). Twenty-eight (58%) patients used methotrexate, 21 used anti-TNF agents and 14 needed corticosteroid infiltration. The population showed low clinical activity in the DAPSA composite activity index (md 3.5; range 0-25). Similarly, US showed a low number of affected joints but US was slightly superior to clinical examination, while US was clearly superior to detect enthesitis and tenosynovitis, particularly tendons of the fingers. The PsAID index (median 0.4; range 0-9.2) showed low correlation with CHAQ (r 0.3) and high with DAPSA (r 0.7); however, the correlation between PsAID and total joint count was low for both clinical and US assessment (r 0.4). The correlation between PsAID and total joint count was moderate for clinical (r 0.5) and low for US (r 0.4). Children with the presence of enthesitis and clinical dactylitis had a higher mean PsAID score than those without (dactylitis; p=0.002, and enthesitis; p&lt;0.001). <h3>Conclusion</h3> The study supports the existence of an atypical pattern of late-onset JPA characterised by a predominance of girls with peripheral involvement and little uveal involvement. Based on our results, dactylitis and enthesitis have a greater impact on the child's quality of life than joint involvement per se. Studies with a larger sample size and/or disease activity are needed to confirm these findings. <h3>Reference</h3> [1]Gossec L<i>, et al.</i> A patient-derived and a patient-reported outcome measure for assessing psoriatic arthritis: elaboration and preliminary validation of the Psoriasis Arthritis Impact of Disease, PsAID questionnaire, a 13-country EULAR initiative. Ann Rheum Dis 2014;73:1012 <h3>Acknowledgements</h3> Sociedad Española de Reumatología Pediátrica (SERPE) <h3>Disclosure of Interests</h3> None Declared.